Sustainable solar-powered hydrogen generation with a silicon nanopillar device with a low carbon footprint

A device system enabling continual hydrogen production under solar light in a water environment is proposed in this study. This system features a self-powered water splitter with a solar harvester from an aluminium-doped zinc oxide/n-type silicon Schottky junction. Thin-film photovoltaic devices are connected in series to reach the reaction potential necessary for the electrolysis of water. Three types of device systems are studied, and their respective hydrogen generation properties are evaluated. The surface passivation effect from only 0.8 nm ultrathin aluminium oxide was found to effectively protect the device surface by withstanding the corrosion of critical solutions for hydrogen generation. In addition, the surface silicon nanopillars create numerical Schottky junctions that can reduce the reaction potential for the electrolysis of DI water from 1.28 V to 0.74 V and achieve a 115 μLh⁻¹cm⁻² hydrogen generation rate. Here, a bias-free and simple structural device system is successfully developed and is advantageous for directly converting solar energy into hydrogen among various water systems. The idea of a sustainable solar-powered hydrogen generation system as well as a future low-carbon footprint design meets the principles of the Paris Agreement.